Dial speed mechanism for a sewing machine



Feb. 14, 1961 s. J. HAMLETT 2,971,484

DIAL SPEED MECEANISM FOR A SEWING MACHINE Filed Jan. 2s, 1959 UnitedStates Patent O DIAL SPEED MECHANISM FOR A SEWING MACHINE Sidney J.Hamlett, Parma, Ohio, assignor to White Sewing Machine Corporation,Lakewood, Ohio, a corporation of Delaware Filed Jan. 28, 1959, Ser. No.789,667 3 Claims. (Cl. 112--220) The invention relates to an adjustablespeed regulator for an electric drive motor ina sewing machine.

One of the principal objects of the invention is to provide a speedregulator in combination with a sewing machine that is directlyresponsive to the output speed of the sewing machine and not directlyresponsive to the output torque.

Another object of the invention is to provide a centrifugally operatedspeed governor in combination with a sewing machine having an electricdrive motor operating at substantially full torque under variabledriving conditions.

Yet another object of the invention is to provide a sewing machine speedgovernor as set forth in the preceding object, that can 4be controlledor regulated from a remotely located control device such as a dial.

Still another object of the invention is the provision of a speedgovernor for the drive of a sewing machine, the drive preferably beingan electric motor, which governor can be so regulated by a portion of anoperators body through a control lever, that the speed of the drive canbe closely controlled up to a selected maximum speed setting of thegovernor. The control lever permits a sewing machine operatortoaccelerate and decelerate the machine speed at a desired rate and/orstop the machine preferably While the operator has two hands free tohandle the article -being sewed. Accordingly, it is desirable that thecontrol lever be operated with a portion of the operators body otherthan the hands, such as a knee, foot, etc., so as to leave the handsfree.

The invention further resides in certain novel features of construction,combinations and arrangements of parts and further objects andadvantages of the invention will be apparent from the followingdescription of the preferred embodiment thereof, described withreference to the accompanying drawings forming a part of thisspecification and wherein the same reference characters representcorresponding parts throughout the several views,- and in which:

Fig. l shows a fragmentary elevational view of a sewing machine standardembodying a preferred form of the invention and with part of the housingremoved to better show the invention;

Fig. 2 is a vertical sectional view along line 2-2 in Fig. l;

Fig. 3 is a horizontal sectional view along line 3-3 in Fig. 2;

Fig. 4 is a fragmentary plan view of a centrifugally operated speedgovernor for the sewing machine drive motor;

Fig. 5 is a side elevational view of the governor; and

Fig. 6 is the other side elevational view of the governor showingconcentric commutator rings and the brushes therefor.

It is to be understood that the invention is not limited to the detailsof construction and arrangements of parts shown in the drawing andhereinafter described in detail, but is capable of being otherwiseembodied and of Patented Feb. 14, 1961 being practiced or carried out invarious ways. It is to be further understood that the phraseology orterminology employed herein is for the purpose of description and thereis no intention to herein limit the invention beyond the requirements ofthe prior art.

Referring to Fig. l, the sewing machine is comprised of a main driveshaft 10 mounted in a standard 11 and driven by an electric motor 12,and also includes a pair of geared together shafts 13 and 14 driven bythe main drive shaft 10 by means of a pulley belt arrangement 15. Themain drive shaft 10 drives the usual mechanism in the upper part of thesewing machine and is carried in the gooseneck of the machine. Theshafts 13, 14 drive the usual associated mechanism mounted in the base,or the lower part of the machine, as is well understood in the art. v

A centrifugally operated governor 16, fixed to the end of shaft 14 forcontrolling the effective driving speed of the motor 12, can beregulated by manually setting a dial indicator 17 to any desired sewingspeed up to the maximum speed capacity of the machine. The dialindicator 17 controls the relative position of a pivotally suspended,dielectric wedge 18 through a sliding linkage mechanism 20. However, theselective positioning of the wedge 18 is not effective tostart the motor12 or to regulate the sewing speed of the machine through the governor16 until the operator moves a control lever mechanism 21 to the right,Fig. l, and presses the wedge 18 to the left. This causes a positivelycontrolled, variable position, electrical contact 23, Fig. 5, to bemoved into contact with a freely suspended, complementary contact 24which is susceptible to outward movement under the action of centrifugalforces arising during the rotation of the shaft 14.

Not only is the Contact 23 brought into Contact with the other contact24 for starting the motor, but the contact`23 is continued to be movedagainst the other contact 24 until it has reached its predeterminedposition as governed by the setting of the dial indicator 17 and theresulting positioning of the wedge 18. Should the shaft 14 have anexcessive rotative speed, the other contact 24 will y outwardly awayfrom the positively controlled contact 23, and the supply of electricalenergy to the motor 12 will be momentarily shut off, caused by thebreaking of the contacts 23, 24. When the shaft 14 slows down due to theload thereon, the contact 24 again closes with the contact 23 and energyis again supplied to the motor 12. The opening and closing of thecontacts 23, 24 occur at such rapid intervals that the starting andstopping of the motor 12 is imperceptible to the operator. But, theresult is that the sewing machine is driven at speeds not exceeding thepreselected desired speed.

More particularly, the shaft 10 is journalled in the upper part of thesewing machine standard 11 and extends through the usual sewing machinegooseneek, not shown. The motor 12 is pivotally supported in thestandard 12 by means of a pair of trunnions 25 in a motor supportbracket 26 as shown and described in applicants copending U.S. patentapplication, Serial No. 758,455, tiled September 2, 1958. A coil spring,not shown, continuously biases the motor 12 in a clockwise direction,Fig. l, about its trunnions 25 so that its rubber drive roller 27frictionally engages and drives a drive wheel 28 fixed onto the shaft10, the outer end of the shaft 10 being provided with a handwheel 30.

The pulley belt arrangement 15, which drives the shaft 13 from the shaft10, is comprised of a pulley wheel 31 on the shaft 10 and a pulley wheel32 on the shaft 13 with a pulley V-belt 33 in driving connection withthe pulley wheels 31, 32.

As pointed out, the shafts 13, 14 are geared together with two meshinggear wheels 34, respectively, for forming a driving connection betweenthe two shafts 1.3, 14, the gear wheels 34, 35 preferably doubling therotative speed of the shaft 14 relative to the shaft 13. It will benoted that the governor 16 is Xed to the en'd of the high speed shaft 14so as to give a greater speed sensitivity and more closely control thespeed of the sewing machine. More specifically, since it is preferablethat the speed of shaft 14 be twice as great as that of shaft 13, thecentrifugal force acting upon the speed sensitive contact 24 will bemultiplied four times over that of the shaft 13 so any change of speedwiil be four times greater on shaft 14 than on shaft 13 and accordinglythe sensitivity of the governor 16 is multiplied.

Each of the contacts 23, 24 are connected into one of the electricalsupply lead lines of a motor control circuit, not shown. The supply leadlines are comprised of a pair of electrical conductor wires 36, 37,respectively leading to the motor 12 from a pair of support blocks 38,39. The blocks 33, 39 are connected to the side of a journal block itlin which one end of each of the shafts 13, 14 is journaled. Theelectrical wires 36, 37 terminate in a pair of electrically conductive,resilient contact strips or elements 36', 37', Figs. 3, 4, 6,respectively, having small, bu'tton-like brushes 36, 37 on the free endsthereof which bear against two coaxial, electrically conductivecommutator rings 42, 43 secured to a flat Side Wall of the disk-likedielectric body 44 of the governor 16, Fig. 6.

The contact 24 is comprised of an electrically conductive, resilient,metal strip with a contact point or button on its free end and isrigidly supported at its otherend by means of an electrically conductiveangle bracket 47 riveted to the body 44 of the governor 16 on the sideopposite to the commutator rings 42, 43. The contact Z4 is electricallyconnected to the outer commutator ring 43 by means of electricallyconductive rivets, such as copper rivets.

The contact 23 is disposed in side-by-side chordal relationship with thecontact 24 and is similarly constructed and fastened at its one end tothe governor body 44 by means of an electrically conductive anglebracket 50 riveted thereto. The contact 23 is electrically connected tothe inner commutator ring 42 by means of electrically conductive rivets,such as copper rivets.

As stated, the contact 24 has one end free toswing outwardly in a radialdirection away from the contact 23 under the action of centrifugalforce. However. the corresponding end of the contact 23 is controlled bya governor actuating mechanism 51, the latter being engaged by the wedge18 upon the actuation ofthe linkage mechanism 21 to the right. Fig. 1,by the operator. It is to be understood that although the lever controlmechanism 21 is shown comprised of a horizontally extending arm 52pivotally connected to and operating an L-shaped dog 53, pivotallysupported upon the base portion of the standard 11 and with its free endadapted to `engage the wedge 18, the lever control mechanism 21 can takeon any of many shapes and forms and can be operated with a part of anoperators body such as a hand, foot, knee, etc., and/or by other knownmeans, it being preferable that the lever 52 not be actuated with oneshands in the instant preferred embodiment so that the hands will remainfree for handling the sewing article. The governor actuating mechanismis comprised of a specially-shaped rocker arm 55 pivotally supportedalong one edge by means of a pintle 56 mounted in a generally U-shapedsupport bracket 57 riveted to the governor body 44. The pivoted end 55aof the rocker arm 55 is connected to an end of a push-pull wire link 58which has its other end fixed to the contact 23 near the outer endthereof so as to provide a greater sensitivity of adjustment. The otheror free end of the rocker arm is provided with a button 5511.

The button SSb is acted upon by a button on one end of a relatively longrocking arm et) pivotally .supported intermediate its ends on a supportange 39a of the support block 39 by means of a pivot pin 61. A coilspring 62 acts against the rocking arm 60 to bias the same in acounterclockwise direction about its pivot pin 61, Fig. 3, so that therocker arm 55 is continuously engaged by the rocking arm d@ and urged ina'clockwise direction about the pintle 56. The clockwise movement of therocker arm S causes the contact 23 to be moved inwardly away from thefreely movable contact 24 in a motor stopping direction.

The spring-biased rocking arm 6i) is adapted to be engaged by thepivoted wedge 18 under the levering action of the dog 53 of the levercontrol mechanism 21.

The wedge 1S is generally -in the shape of a right triangle with itssloping hypotenuse side being engaged by the dog 53.

The lower end of the sliding linkage mechanism 2i) has the Wedge 13pivotally suspended therefrom. The sliding linkage mechanism 2t? iscomprised of a vertical ram 64 slidably connected to and guided on'twovertically spaced guide screws 65 threaded into the wall of housing 11and extending through two guide slots in the ram 64. The ram 6ft ismoved vertically downwardly by turning the dial indicator in a clockwisedirection, Fig. l, and upwardly by turning the indicator 17 in acounterclockwise direction. The position of the dial indicator 17 vinFig. l preferably represents the lowest machine operating speed and notthe motor stop position in the instant embodiment.

The dial 17 is connected to the ram 64 by means of aY crank arm 66 and alink 67, which is pivotally connected to the free end of the crank arm@56 and to the upper end of the ram 54 by means of a sliding slot,pivotal connection. The crank arm do is xed to the dial 17 so as to turntherewith. Both the dial 17 and the crank arm 66 rotate in a journal 63.

It will be noted that the dial 17 is provided with a pointer 17a havingan index mark thereon and that the pointer 17a cooperates with theindicia marks on the outside of the standard 11. The indicia marks inthis instance are scaled from sewing speeds of 2 to 12 indication.

From the foregoing it is apparent that as the dial 17 is turned in aclockwise direction, Fig. 1, that the wedge 18 will be further projectedbetween the actuating mechanism 51 and the lever control mechanism 21.Tnistcauses the distance between the two mechanisms 21, 51 to beincreased and accordingly permits greater speeds of the sewing machineby moving the controlled contact 23 a greater distance toward the leftand into iirmer engagement with contact 24, Fig. 5, so as to require agreater centrifugal force to cause the contact 24 to move away from thecontact 23 and break the motor control circuit. The dog 53 of the levercontrol mechanism 21 is limited in its movement to a predeterminedamount -in both directions, about its pivot pin, Fig. l, by the sideslil and 71 of the opening in the bottom wall of the standard or housing11 through which the dog S3 protrudes.

The preferred form of the invention having been described, it will beunderstood that the invention can be modified to adapt it to variouscircumstances and conditions and it is accordingly desired to comprehendwithin the purview of this invention such modifications as may beconsidered to fall within the scope of the appended claims.

Having described my invention, I claim:

1. In a sewing machine, a drive motor, an adjustable centrifugalgovernor including a iirst contact movably responsive to centrifugalforces and va second contact cooperating therewith for controllingenergization and deenergizaton of said motor, selectively settablecontrol means operable to adjust said second contact relative to saidfirst contact to establish a preselected speed of said motor, saidsettable control means being ineffective to close said first and secondcontacts and additional control means operable by an operator to adjustsaid second contact relative to said first contact without disturbingthe adjustment of said second contact effected by said settable conrolmeans for energizing and de-energizing said motor and for varying thespeed of the motor up to said preselected speed.

2. In a sewing machine, a drive motor, a centrifugal governor includinga first contact movably responsive to centrifugal forces and a secondcontact cooperating therewith for controlling energization andde-energization of the motor, selectively settable control meansincluding a part movable in one direction to adjust said second contactrelative to said first contact to establish a preselected speed of saidmotor, said settable means being ineffective to close said first andsecond contacts, and means including a control element movable under thecontrol of an operator to displace said part in another directiondifferent from said one direction to adjust said second contact relativeto the first contact without disturbing the adjustment of said secondcontact effected by said part for energizing and de-energizing the motorand for varying the speed of the motor up to said preselected speed.

3. In a sewing machine, an electric drive motor, a centrifugal governorincluding a first contact movably responsive to centrifugal forces and asecond contact cooperating therewith for controlling the energizationand deenergization of said motor, mechanism including a pivotal rockerarm for adjustably varying the operative position of said secondcontact, a spring acting on said rocker arm to move the latter in onedirection for normally separating said contacts, means under the controlof an operator for moving said rocker arm against the spring loadincluding a movable actuating member, a wedge element mounted forpivotal movement about a horizontal axis and interposed between saidactuating member and said rocker arm to operatively connect saidactuating member and said rocker arm, and selectively settable means formoving said wedge element in a vertical direction to move said rockerarm against said spring to selectively vary the position of said secondcontact for establishing a selected speed of said motor, said settablemeans being ineffective to cause engagement of said first and secondcontacts, said actuating member when moved by an operator beingeffective to pivot said wedge element about the horizontal axis toenergize and deenergize said motor and to vary the speed of the motor upto said preselected speed.

References Cited in the file of this patent UNITED STATES PATENTS2,337,066 Schmitt et a1 Dec. 2l, 1943 2,477,150 Snyder et al July 26,1949 2,588,301 Snyder Mar. 4, 1952 2,850,996 Howard Sept. 9, 1958FOREIGN PATENTS 623,688 Germany Ian. 2, 1936

